The present invention generally relates to power hand tools and more particularly to a power hand tool with a quick attachment release system.
Small rotary hand tools have been marketed for many years for use in carrying out woodworking and metal working tasks by hobbyists as well as commercial artisans. An example of such is produced by Dremel, which also produces many accessories for these rotary hand tools. Such small rotary hand tools are generally cylindrical in shape, and have a motor unit with a rotary output shaft that is adapted to connect to a number of accessories. The drive unit of many recent models of such rotary hand tools is relatively small, lightweight and capable of being easily used. The tool has a small but powerful electric motor that is capable of driving an output shaft at high speed, and a rotary implement can be typically attached to the tool""s output shaft, which is axially aligned with the length of the tool.
There are several accessory attachments such a flexible cable, a grout removal guide or cutting guide, a chain saw sharpener among others, which are attached directly on the rotary hand tool for use. It is the current practice to attach these accessories by threadably mounting them onto the rotary hand tool. The problem with this method is that it is inconvenient and takes more time than is desired to screw the accessory on and off the rotary tool. Another disadvantage is that the accessory attachment often tends to rotate relative to the tool body during use or is not properly aligned for effective performance.
Accordingly, it is a primary object of the present invention to provide an improved rotary hand tool that includes a quick release attachment system that allows users to snap-fit an accessory attachment onto the rotary hand tool, yielding a quick engage/disengage feature.
Another object of the present invention is to provide an improved rotary hand tool that prevents rotation of the accessory attachment relative to the tool body during use and precisely aligns it for effective performance.
The above-listed objects are met or exceeded by the present rotary hand tool with quick release attachment system, which features a snap-fit connection between the rotary hand tool and accessory attachments. A spring-loaded ball in a mating attachment engages a groove on the rotary hand tool, which yields a quick engage/disengage feature.
Another feature of the present rotary hand tool with quick release attachment system is a keying feature in the nose end portion of the rotary hand tool, which prevents the attachment from rotating relative to the tool body during use and precisely aligns it for effective performance. A non-circular shaped extension, which may include any polygonal, oval, or star shape, is configured on the nose of the tool, which mates with a complementary non-circular shape opening in the mating attachment. This prevents rotation of the mating attachment relative to the body of the tool.
More specifically, the present invention provides a rotary tool with a quick release attachment capability. The rotary tool has a housing that encloses a motor, and the housing has a central axis, a non-operational end portion and an operational end portion. There is a nose portion formed at the operational end portion, and the nose portion has an outer annular groove disposed generally perpendicularly of the axis. The nose portion also has a non-circular element at the outer end thereof parallel with the central axis. A rotatable shaft is connected to the motor and is located along the central axis.
The accessory attachment includes a central cavity, a mating and connection end portion and a working end portion. A non-circular mating element is formed in the central cavity that matingly engages the non-circular element of the rotary tool. There is also a biased mating and connection element provided on the accessory attachment, which faces the central cavity. This biased mating and connection element engages the annular groove of the nose portion when the accessory attachment is fitted onto the rotary tool.